BZOJ 1537 二维偏序

 1
 2 #include <iostream>
 3 #include <cstring>
 4 #include <cstdio>
 5 #include <algorithm>
 6 #include <map>
 7 using namespace std;
 8 const int Maxn=100100;
 9 int n,m,k,c[Maxn],F[Maxn];
10 map<int,int> M;
11 struct Info{int x,y,z;}P[Maxn];
12 inline bool cmp(Info A,Info B) {return A.x<B.x || (A.x==B.x && A.y<B.y);}
13 inline int Max(int x,int y) {return x>y?x:y;}
14 inline int Lowbit(int x) {return x&(-x);}
15 inline int Query(int x){int Ret=0; for (int i=x;i;i-=Lowbit(i)) Ret=Max(Ret,c[i]); return Ret;}
16 inline void Update(int x,int y) {for (int i=x;i<=k;i+=Lowbit(i)) c[i]=Max(c[i],y);}
17 int main()
18
19 {
20     scanf("%d%d%d",&n,&m,&k);
21     for (int i=1;i<=k;i++) scanf("%d%d%d",&P[i].x,&P[i].y,&P[i].z),M[P[i].y]=1;
22     int Cnt=0; sort(P+1,P+k+1,cmp);
23     for (map<int,int>::iterator it=M.begin();it!=M.end();it++) it->second=++Cnt;
24     for (int i=1;i<=k;i++) P[i].y=M[P[i].y];
25     for (int i=1;i<=k;i++)
26     {
27         F[i]=Query(P[i].y)+P[i].z;
28         Update(P[i].y,F[i]);
29     }
30     int Ans=0;
31     for (int i=1;i<=k;i++) Ans=Max(Ans,F[i]);
32     printf("%d\n",Ans);
33     return 0;
34 }

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